In geometry, a translation is the shifting of a figure from one place to another without rotating, reflecting or changing its size. This is done by moving the vertices of the figure the prescribed number of spaces on a coordinate plane and then drawing the new figure.
These PFDs are designed to keep the wearer in a vertical position, but it is the wearersâ responsibility to maneuver themselves into a face-up position. Type III PFDs will keep unconscious wearers face-up just as well as a Type II vest.
1 If your mouth is not well above the water, get a new PFD or one with more buoyancy.  A PFD is designed not to ride-up on the body when in the water. But, when a wearer's stomach is larger than the chest, ride-up may occur. Before use, test this PFD in the water to establish that excessive ride-up does not impair PFD performance.